Refrigerating apparatus



April? 8 1924. V

F. E. NORTON REFRIGERATING APPARATUS April 8, 1924. 1,489,395

7 F. E. NORTON REFR I GERATI NG APPARATUS Filed J 50, 1919 3Sheets-Sheet 2 Invenwwv F. E. NORTON REFRIGERATING APPARATUS April 81924. 1,489,395

Filed Jan. 30 1919 3 Sheets-Sheet 5 Patented Apr. 8, 1924.

UNITED STATES PATENT or fice.

ram) E. NORTON, or woaonsrnn, massaonusm rs, assxenoa' 'ro.r'nrrsarnssnoa'ron coaronarxon, or woacns'rna, MASSACHUSETTS, aoo'nron'erxon'or DELAWARE REFRIGERATIN G APPARATUS.

Application filed January so, 1919; sem 80:274.,080.

To all whom it may concern:

Be it known that I, Fnnn E. NORTON, a citizen of the United States,residing at Worcester, in the county of Worcester and Commonwealth ofMassachusetts, have invented a new and useful Improvement. in aRefrigerating Apparatus, of which the following, together with theaccompanying drawings, is a specification.

The present application has for its subject matter the apparatus setforth and described, but not claimed in my process Patent, No.1,292,958, dated January 28, 1919. The present invention, in common withthat 1 of my aforesaid process patent relates in general to the art ofrefrigeration, and has particular reference to the attainment ofextremely low temfiperatures by the use of a gaseous working uid. Thelowtempera tures thus attained ma he used, if desired, in securingextreme re rigerative effects; or the invention may be utilized for thepurpose of liquefying, in whole or in part, the gas, and if desired,this liquefaction, if the gas be a mixed gas, may be employed inconnection with suitable distillation a encies to efi'ect the separationof the gas into its constitutent elements. Moreover, as will be shown,the invention may with advantage to be utilized for the cheap andefiicient production of power, in a form available for the production ofuseful work.

The present invention contemplates the attainment of marked improvementsin efat ficiency and capacity over the processes of this classheretofore lrnown; the principles of the invention and the various stepsemployed in the application of said principles to the accomplishment ofthe desired results to are fully set forth in the following descriptionand pointed out in the annexed claims, reference being had to theaccompanying drawings which illustrate, diagrammatically, threedifferent arrangements of appa- "Mi ratus by means of which the novelprinci- 'ples may be put into practice.

Referring to said drawin s, wherein like reference characters are use toindicate like parts in the several views,

of one arrangement of apparatus which may be employed, and which is mostSusceptible to the explanation of the novel and useful steps whichconstitute my invention.

Fig. 2 is a fragmentary illustration of a modification of the apparatusshown in Fig. 1, introducedherein for explanatory purposes.

Fig. 3 is a diagrammatic representation of an arrangement of apparatusillustrative of what I now contemplate as being a preferable arrangementfor the application of the aforesaid noveland useful steps.

- Fig. 4: is a diagrammatic representation of an arran ement ofapparatus illustrating the application of certain of the novel steps ofmy invention to a system which may be said to be typical, in a generalway, of the refrigeration and liquetaction systems of the prior art.

It is to be understood, however, that the carrying out of my inventionis not in any Way confined to the employment of the here in described orany other particular or rangement of apparatus, nor to the hereindescribed methods of utilizing such apparatus, except in 'so far asspecified in "the appended claims; the drawings and description beingillustrative merel and disclosing only a few specific app ications whichI now regard as being advantageous for the accomplishment of the novelsteps hereinafter set forth.

As heretofore practiced, systems otthis class, which may or may notinvolve the complete liquefaction of the working fluid, depending uponthe ultimate purpose .which the refrigeration is to be applied, haveshown extremely low efficiency and capacity for refrigeration, by reasonof the demands a:

made upon the external cooling agency in attaining the desired lowtemperatures, such systems, therefore, requiring large expenditures ofpower for sug'iplying the necessary refrigerative efiect. In suchsystems,

especially where liquefaction for the ultimate purpose of separation iscontemplated, preliminary compression of the gas to be till separated,and sometimes even higher compression of the gas used in the externalcoolin agency, has invariably been employeti in order that condensationmay occur at a fairly high temperature. Since an expansion devicereturns useful Work in less and less degree as the temperature of thefluid to be expanded is lowered, this preliminary compression of the-gashas, in the past, been resorted to in'order that the expansion devicesof such systems may work at as high a temperature as possible. In suchprevious systems, however, this small apparent ain in the efliciency ofthe external coo ing agenc has been more than offset by the cost ofighly compressin the working fluid, since substantially all 0 the workofthis compression is dissipated in the system owing to the factthat therelease from pressure of a large portion of the working fluid is reliedupon to effect its liquefaction, and this occurs without any productionof external work. That is to say, in all such prior systems the .gasissuing from the system in countercurrent to the incoming com ressedgas, irrespective 4 of whether it has passed through theliquid state, orwhether, if a mixed gas, its components' ably under such a low pressurethat the re covery of any power therefrom is out of the question.

According to the present invention, the

step of the preliminary compression may be wholly omitted; or at leastthe degree of comprmsion may be substantiall reduced, the gas may betaken in under su stantially atmospheric conditions, and it may becaused to leave the system under a much higher pressure, in such ablefor furnishing aconsiderable portion of the power required to producethe desired refrigeration and liquefaction of the working fluid. In thisconnection, the adaptation of the principles underlying my invention tothe eiiicient and cheap production of power in addition to the specificutility of said principles for the liquefaction and separation of gases,such as air, will be readily understood, it being clear, from whatfollows, that the working fluid employed in the system is brought to ahigh pressure by the minimum expenditure of work, and in "this conditionis available as a motive fluid, gith or without the addition of externaleat.

lVhile it is clear that the mechanical imperfections of any givenapparatus invariably preclude the attainment of a perfect efiiciency,and while it is also apparent that a process of the character herein setforth is always limited by such mechanical imperfections, still it isunquestioned that the final efiiciency of such a system will attain thehighest degree only when the several issue in separated form,- isinvari-gf a condition as to be avail-v changer, designated actionsoccurring therein are reversible in character, at least in theory. Ithas been shown that in prior systems of this class, the actions areirreversible. That is to say, the flow of heat from a higher to a lowertemperature, or level, without effecting external work, as by therelease of pressure above described, 15 a characteristic action of priorsystems of this class, and as such, is an irreversible action, i. e., anaction requiring'an expenditure of work to restore the substance to itsoriginal condition. According to the present invention, the several heatexchanging actions between different portions of the fluids in differentstages of the process reversible, at least in theory, incontradistinction to the wholly irreversible actions which arecharacteristic of prior processes of this class; as a conse uence, in

theory at least, the work require in order will be shown to besubstantially to effect the desired refrigeration is simply I that workwhich is necessary in order toimperfections of overcome the mechanicalthe apparatus, it being assumed, for the present purposes, that theinleakage of external heat is properly guarded against by the provisionof suitable insulation.

With reference to the application of the principles above set forth tothe attainment of the' objects mentioned, the Fig. 1, together with theseveral steps of the process which ratus therein illustrated, will nowbe set forth in detail. 1 Referring to Fig. 1, the gaseous working fluidused in the process is led, under atmospheric pressure, or under only anominal pressure, into a passage 1 of a heat inter as a whole by thenumeral 2. This interchanger, which is herein represented in purelyconventional form,

as and advantages her'cinbefore diagrammatic illustration of,

are carried out by the appshas a countercurrent passage 3, in intimatethermal relation to the passage 1. I have selected, for purposes ofillustration, a form of apparatus in some respects resembling that shownin my United States Letters Pat ent No. 1,264,845, issued April 30,1918; in common with the invention disclosed in said Letters Patent, theworking fluid, after liquefaction under low sage 1, in the mannerhereinafter set forth, is transferred to the passage 3 by a pump orother ressure increasing maintains it in said passage 3 under a pressureconsiderably in excess of the pressure prevailing in passage 1. Theressure prevailing in the assage 3 is obviously due to the resistanceimposed against the outflow of vapor from the upper end of said passage;in forcing liquid in the bottom of passage 3, the pump 4 must'put itunder suiticient pressure to overcome the pressure prevailing in saidpassage, which, as above pressure in the pas-- device 4, which stated,is higher than the pressure prevailing in passage 1.

In common with the invention set forth and described in said UnitedStates Letters Patent, the high pressure liquid in passage 3 is to beevaporated at such increased pressure and returned in countercurrentthrough tion of temperatures at any given level by heat interchangebetween the two passages 1 and 3, is contemplated, and in otherapparatus of this character, the temperatures are lower, the lower thelevel reached in said interchanger. To effect this evaporation in thepassage 3, an expedient,

somewhat similar to that employed in the process of said United StatesLetters Patent, but difiering therefrom in certain particulars afi'ectinthe ultimate results obtained thereby, is adopted, the same being hereinillustrated as a means for transferring the latent heat of condensatwnfrom the vapor being condensed just above the I surface a to evaporatethe warmer liquid at the surface-b," 0 this end, a coil 5 may beimmersed in the' liquid formed within the passage 1 of-the interchan erand a compresbe mostly li uid, and

period, of a weig sor 6 may be interposed etween this cold coil 5 andthe warm end of a coil 7 partly immersed in the liquid contained in thepassage 3. Said coil 7 communicates at its cold end with an expander ornozzle 8, and the latter is connected to the inlet side of the coil 5,thereby forming a closed circuit. Said circuit may be en plied with acirculating fluid having a hbiling oint at the same, or a lower,temperature t an the fluid to be condensed at the surface a. Assumingthat the compressor 6 works at a slightly higher pressure than the pump4-, and that the fluid used in said circuit is the same as the workingfluid, it will be clear that the circulation by com ressor 6, during agiven t of fluid equal to or slightly in excess of the weight of workingfluid entering passage 1 during the same period, will effect thistransfer of heat con tents, as follows:

This circulating fluid assing tothe coil 5, after its pressure is reeased in expander may, under the conditions assumed above, whilecondensing the fluid above t e surface a by extracting the latent heatof condensation therefrom, it will be substantially evaporated. Thevapor, or the mixture of liquid and vapor from the common with coil 5,passing to the compressor 6, has its pressure and temperature raised bysaid compressor. Passing in substantially gaseous form to the coil 7, iteffects the evaporation of liquid at the surface 6, by transfer of itsheat to said li uid, and is itself condensed thereby in w ole or inpart. The

subsequent release of pressure from said circulating fluidin the nozzle8 causes its return to the coil 5 in condition to repeat thecondensation at the surface a in the manner above described. I

The actions, above described, will be carried out, under readily, merely5 to be slightly working vapor the conditions assumed, very by causingthe liquid in coil colder than the low pressure to be liquefied at thispoint,

, in order to promote the transfer of heat contents in the properdirection, and it will be seen that the difference in temperature relied upon to effect this transfer of heat units between the fluids canbe made as small as desired simply by increasing the contact surfaces ofthe coil. The same is obviously true of the action occurring in the highpressure passage 3, in which a all htly greater pressure or temperaturewit in the coil 7 insures the necessary exchange of latent heats. Itwill be clear that other conditions afi'ecting the pressure,temperature, composition, and quantityof the circulatory transfer fluidmay be adopted, within a wide ran e, without departing from theprinciples of t e actions above set forth, since the foregoingassumptions were made merely for purposes of explanation. As has beenshown, the transfer of the relatively large quantities of heat betweenthe working and the circulating'fiuids occursin each case with only avery slight temperature difference; thus each action as descri ed above,of itself, therefore, approaches reversibility as closely as themechanical imperfections inherent in the a paratus will permit. That isto say, the a sorption and rejection of latent heat by the working andcirculating fluids, as described above, takes place under substantiallyconstant temperature and hence with the highestflpossible efliciency.Obviously, the cir culating pressed and expanded in the compressor 6 andnozzle 8 need not be confined to the coils 5 and 7, as above described,but may be constituted by fluid taken directly from and returned to thesupply of working fluid present in the passage 3 of the interchanger, asfully set forth in my aforesaid United States Letters Patent, in whichcase the quantity of fluid circulated in the heat transfer system would"be in a redetermined proportion to the quantity 0 working fluid handledby the pump 4. The above described use of the, circulating coil -7 isadopted simply for the sake of clearness and to avoid confusion in theexplanation of my process.

fluid which is alternately com- As fully set forth in my said UnitedStates Letters Patent, the high pressure gas thus evaporated at thesurface I) has, by reason of its increased specific heat, a greatlyincreased heat absorbing capacity; in other words, it is capable ofremoving from the system a greater amount of heat per degree oftemperature than is brought in by the same weight of fluid entering thepassage 1. In the present process, a portion of this available excesscooling effect may be utilized in removing from the transfer fluid anysuperheat, as would result from the introduction to the compressor 6 ofsaid fluid in the form of a saturated vapor. As herein shown,'the coil-7extends above the liquid level I), in the passage 3, it being assumed,for urposes of illustration, that superheating o the transfer fluid, toa degree indicated by the temperature level 0 of the interchanger, hasoccurred. The liquid, therefore, does not rise to level 0, but boils offso as to remain at a level somewhat below 0, the exact position ofwhich, I), is obviously dependent wholly on the amount of superhe'at.Between the levels I) and c the high pressure evaporate with itsrelatively high heat absorbing ca pacity, accomplishes the removal ofthis superheat.

As pointed out in my said United States Letters Patent, there is adeficiency in the cooling efiect available for condensing the incominglow pressure gas near the ower end of passage 1, notwithstanding thefact that in the process of, said Letters Patent the temperature of saidgas is lowered, by heat exchange with the high pressure liquid; thisdeficiency is due to the fact that the substance under low pressure hasgreater latent heat than the same substance under high pressure. In theprocess of said Letters Patent an expansion engine, or other equivalentcooling agency, was required to supplyv this deficiency in coolingeffect and, as shown, it had to perform its work of cooling at theextremely low temperature necessary to effect condensation in the lowpressure passa e of the system.

In t e present system, not only is the necessity for an external coolingagency working at such a low temperature Wholly avoided, but, ifdesired, the high pressure liquid in passage 3 may impart all of itscooling effect to the transfer fluid i-n coil 7 since such coolingeflect is not essential to the cooling of the low pressure vapor inpassage 1. According to the present invention the excess of coolingeffect present in the high pressure gas above the level 0 is employed tosupply the deficiency of cooling effect in the cold end of the lowpressure passage 1, and to this end the arrangement of apparatushereinafter described may be employed, although it will apparent that myinvention is not limited in any way to the use of such an arrange highpressure vapor of passage ment, the particular illustration hereinemployed being adopted merely for the sake of clearness in explanationA. compressor 9 is connected with a coil 10 located in the warm end ofpassage 3. The coil 10 communicates with an expansion engine 11, whichin turn is connected to a second coil 12 disposed in the cold end of lowpressure passage 1. Said coil 12 is connected to the inlet side ofcompressor 9, thereby forming a closed circuit. Said circuit is suppliedwith a circulating flui which may be the same as the working fluid, andas in be case of the circulating fluid in the system 5, 6, 7 and 8, itmay, for illustrative purposes be assumed that the. weight of fluidcirculated by the compressor 9, during any given period, is the same as,or slightly in excess, of the weight of the working fluid entering passae 1 in the same period, the compressor 9 wor ing, as before, betweensubstantially the same pressures as the pump 4.

The action under the conditions assumed is approximately as follows:-The fluid in coil 10, at substantially the same pressure as essivelythe vapor in assage '3, is progr cooled, by heat interchange therewith,to the temperature prevailing at level 0. There after, said circulatingfluid is expanded to atmospheric pressure through expander 11, beingcooled thereby to a temperature approximately that at the level a.Returning through the coil 12, in countercurrent to the incoming gas inpassage 1, it progressively cools said gas to the temperature of lowpressure liquefaction, namely that at level a and is itself warmed up tothe temperature 0.. From this point it passes'to the compressor 9, andafter its original pressure and temperature have been restored, it 15again passed through the cycle above described. Thus the cooling eifectof the escaping high pressure vapor is applied to the incoming owpressure vapor to cool the latter from a to. a; it will be clear that,approximately, the same conditions prevail with respbct to this transferof heat .contents as prevail with respect to the transfer of latentheats by the system 5, 6, 7 and 8, above described, namely that at anygiven point, assuming only a slight difference in temperature in favorof the direction in which it is desired that the exchange should takeplace, the actions above described occur under substantially constanttemperature, and hence, approach reversibilty as closely as themechanical imperfections of the apparatus will permit. Moreover, in thepresent instance, it will be clear that owing to the greater coolingeffect available in the 3, it is highly desirable to apply this coolineffect at the cirt where it is most neede and the fact that this pointis at the cold, rather Wide range anson than at the warm end of theinterchanger, does not in any way prevent or retard the transfer of heatcontents in the manner above described, even thou h it does necessitatea flow of heat from cl temperature. As in the previously describedcirculatory latent heat transfer system, a is permissible for variationof the pressure, temperature, composition and quantity of the transferfluid from the conditions assumed above,which were merely for purposesof explanation. Obviously, also, the use of the coils 10 and 12 is notat all essential, the same being shown and referred to merely by way ofvarious actions plainer.

In the application of the novel rinciples above set forth to the actualworking conditions existing in refrigeration systems of this class, itwill be obvious that as many circulating systems corresponding to thesystem 9, 10, 11 and 12 may be used as is necessary to effect the dropin temperature from the'warm end of the interchanger to the cold endwhere liquefaction under low pressure takes place. For the sake ofclear- 7 ness in illustration, the present application has been confinedto the showing of a single circulatii'ig system of this character forthe purpose of applying the coolingefi'ect of the high pressure -vaporto the low pressure vapor at a lower-temperature, but it is clear thatfor practical working conditions where the working fluid is brought inunder substantially atmospheric pressure and is liquefied, the'appliciation of this high pressure cooling effect will be best servedby the provision of a plurality of circulating systems corresponding tothe system 9, 10, 11 and 12, each adapted to work within a range oftemperatures of less extent than the total temperature drop required.

The establishment of the conditions illustrated in Fig. 1 may beassumed; or it may be shown that such conditions may be established andthat after their establishment the system will operate continuously, inthe manner hereinafter described, to take the working fluid, brought inat atmospheric pressure, through the liquidstate as shown. In order tostart the operation, the compressor 9 and expander 11 may be operated byany source of available power and the heat of compression aboveatmospheric temperature during this starting may be radiated or absorbedin any suitable manner. Under these conditions, provided the compressor6 is inoperative, or operates only without pressure, by the openingofnozzle 8, the system'will progressively become colder until the gasbegins to be liquefied at a, whereupon the normal working conditions maybe established. It has been shown that the cooling effect of theoutgoing substance can be applied to the refrigeration of the incomingower to a hi her' making thethe weight entering substance in a highlyeflicient manner, and that the resulting condensation of the lowpressure vapor can be applied to effect the evaporation of the highpressure li uid. Consequently, the necessity for externa refrigeratingagencies is confined only "to the overcoming of the mechanicalimperfections of the apparatus, and to the cooling of the incoming vaporin passage 1 between substantially atmospheric temperature and thetemperature prevailing at the level 0 in the interchanger. readilysupplied at relatively low expense by any 1 well known type of externalcooling agency, such as a. coil 13, expander 16, water cooler 15, andcompressor 14, which latter, for example, may work between the samepressures as the other compressors 6 and 9, and may circulate, ina giventime, a weight of working fluid corresponding to the low pressurepassage 1 during the same time. In this way the ex ternal coolingagency, which represents, as will be shown, the bulk of the externalpower required to operate the system, need only attain a very limiteddegree of coldness, which constitutes only a small portion of the totaltemperature drop required. That the ex ternal cooling agency abovedescribed constitutes, in theory at least, the only external workrequired to o erate the system, is shown as followsz-lnder theconditions assumed, the compressor 6 handling the same quantity of fluidand working between the same temperaturw and pressures as the expander11, requires, in theory, the same amount of external work as isdelivered by This cooling effect may be v said expander. The above alsoholds true for the compressor 9 and the expander 16; that is, the workrequired by the former is balanced by the work delivered by the latter.Also, the expansion through nozzle 8, even though at an extremely lowtemperature, is sufficient, in theory at least, to supply the smallamount of work required'to o crate pump 4, it being clear that these twoevices have also been assumed to handle substantially equal quantitiesof fluid, between substantiall .the same pressures and at the sametempera ures. Therefore, outside of the power required to overcome thelosses due to the mechanical imperfections of the several pumps, comressors and expanders above referred to, t ere remains only the work-required to operate the compressor 14, in order to make the processcontinuous. The high pressure vapor leaving the passage 3 may e heatedby any external source of heat 17, and then used in a highly efiicientmanner in an expansion'motor 18 to develop all, or at least aconsiderable portion of the power required'to o "crate the compressor14. Ohviously, the e co to which this high pres sure vapor is eated, i.e., has energy imparted to it, is a measure of the work which theory theheat remove it is possible to develop in the motor 18, in excess of theamount available due to its ressure at atmospheric temperature.

WhileI have shown a high pressure va r from the passage 3 as being usedto deve op a portion of the power required to operate the process, byexpansion in the motor 18, it will be clear that this vapor, f desired,may be applied to the refri eration of the incoming low pressure vaportween atmospheric temperature and the temperature of the level a byallowing it to. expand suitable expansion engine 19, Fig. 2, and byreturning said expanded and cooled fluid through a coil 20 or other heatexchanging agency disposed in the warm end of passage 1.' The foregoinghas'been pointed out simply for the purpose of shown that in vapor onthe low pressure side of the countercurrent apparatus substantiallybalances the heat absorbed by outgoing vapor in the high pressure sideof the countercurrent apparatus. In other words, that excluding texternal work required to overcome the mechanical imperfections of theapparatus, and that required external heat, plied since the expander 19,replacing ex-' pander 16, delivers enough ower to operate the compressor9. This is o vious since sai expander 19 and said compressor 9 handle toabsorb the inleakageo the same quantity of fluid at the same temperatureand pressure.

It has been shown above that the process is workable under the specificconditions assumed where the total temperature range vapor,

The invention, however,

limited to this of moisture, at t the level a to atmospheric is that oftwo or more successive substantially adiabatic compressions of a dry gasor whereby the temperature at the level 0 is fixed, once the pressuresare assumed. is not in any way restriction. -Hei'etofore it has beenassumed that the vapor drawn into the compressor 6 is dry, but ittisobvious that there is alwa ssome condition or state elower pressure,which will result in this vapor being just saturated after adiabaticcompression, and it may be assumed that the fluid leaving the compressor6 is in such a dry or saturated state, that is, without superheat. Undersuch conditions, the liquid in passage 3 may rise to the level 0 in theinterchanger'; and under this condition the from that at difference intemperature bet-ween'c and a is less than under the conditionsheretofore assumed, although the pressure will'remain the same. Itfollows, since the compressor 6 may take in a wet vapor and discharge a'dry saturated vapor at higher pressure, the expander 11 likewise maytake in a dry saturated vapor and discharge fluid which'ispartly liquid;the latter, while evaporating in coil 12, may

in a" d from the incoming no other'work need be supwhich limited to theprevalence of particular tem-- perature and pressure conditions in theheat transfer systems, nor to the maintenance of any definite relationsbetween the temperatures at the levels a and 0, and that at the warm endof the interchanger. It will be clear, therefore that and 0 may beassumed, and any corresponding pressure ranges within the heat transfersystems may be adopted. It will also be seen that the cooling effect ofthe high pressure vapor in passage 3, .between the temperatureprevailing at the level 0 and at the atmosphere, is always sufficient,if collected in a substantially reversible manner and applied in asubstantially reversible manner,

fto cool the low pressure vapor in passage 1 from the temperature at 0to that at a, even though the specific means, as heretofore shown anddescribed, be varied over a wide range of pressures and temperatures. Itwill also be evident that these results depend in no way on the specificsubstance employed except that it be a fluid.

The foregoing detailed explanation of the operation of my invention, inconnection with the particular type of apparatus shown in Fig. 1, ischiefly useful in graphically demonstrating the principles underlyingthe 1 on same, by virtue of which all of the severa heat exchangingactions are caused to take place in a substantially reversible manner,whereby the process can be carried out with a minimum' expenditure ofpower. Obviously, I am in no sense limited to the use of apparatus ofthis character, nor even remotely resembling the same, in the sense thatthe various heat exchanging actions ma be as clearly and definitelytraced out an shown to'be substantially reversible in character, Infact, I now contemplate, as a much simpler and more practical form ofapparatus suitable for the application of the aforesaid principles, themodified form of apparatus shown in Fig. 3 of the drawings, will beshown to be substantially the equivalent, in all respects, of theapparatus shown in Fig. 1, although not as susceptible to actualdemonstrative proof of the actions occurring therein, as is said firstdescribed The final result as regards the apparatus.

is the same in both working fluid however, cases.

Referring the passage 1 of an interany temperatures at a.

changer 2 at atmospheric, or only a nominal, pressure, as before, and ispassed through the liquid state with an increase of pressure by the pumpl'before being evaporated in the passage 3 at the level 6-0. Theapparatus herein shown for effecting the transfer of heat from the levela to the level b-c in order to evaporate the liquid at said upper leveland to condense the vapor near the lower level is substantially the sameas previously described in connection with- Fig. 1, although it will beapparent that the cirzulation of the transfer fluid, and the weight ofsaid fluid passing through a part of the system is to some extentvaried, owing to the particular relations existing between said systemand other portions of the apparatus, as hereinafter pointed out. Thecoil 21 corresponds to the coil 5 of the first described form, but isextended above the level a up to the level b-c, so that its cooling eflect may be applied to the low pressure vapor between the levels a andbc. The heat transfer fluid, which may be assumed to be ofthe, samenature as the working fluid, after circulation through this coil, is ledto the compressor 22, working at substantially the same pressure as pump4, and thence through a coil 23, leaving which it is expanded through anozzle 24 and returned to the coil 21 in the manner previouslydescribed. The evaporation of the high pressure liquid at the level 6-0is thus effected. As in the former case the coils 21 and 23 are shownmerely for the sake of clearness, it being obvious that the circulatingfluid could be withdrawn directly from the fluid in the passages 1 and 3of the interchanger.

in order to apply the excess cooling effect of the high pressure vapor,a coil 25, corresponding substantially to the coil 10 of Fig. 1, may bedisposed in the passage 3. The fluid circulating through 0011 25 maycome from a high pressure compressor 26, working at a pressurecorresponding substantially to the critical pressure of said fluid;leaving the compressor, it is cooled to atmos heric temperature by awater cooler 27 hefore entering the coil 25. From the coil 25 thecompressed and cooled circulating fluid expands in an expansion engine28, and the low pressure exhaust from said engine is led to the inletside of the compressor 22, where it is mixed at 30 with at the surfacea.

sage 1 during the same time, at atmos heric pressure and temperature;obvious y, as previously pointed out, the coils 25 and 29 are shownmerely for the sake of clearness, since the fluid thus circulated could,with suitable pressure conditions, be taken from and discharged directlyinto the two passages 1 and 3 of the interchanger without varying in anyWay the ultimate result.

In the operation of the above described apparatus, the conditionsillustrated in Fig. 3 may be assumed, or if desired, they may becreated, sor 26 so as to produce a pressure equal to or higher than thecritical pressure of the transfer fluid. The said compressor and theother elements of the circulatory system connected thereto, therebybecomes an external cooling agency suflicient, in time, to efl'ect thedesired liquefaction under low pressure During this starting period themotor 18, which, during actual operation of the process, is driven bythe heated high pressure evaporate from the passage 3, as in thepreviously described system, may be drven by steam or other externalmeans to effect the above described operation of the compressor 26.Owing to the phenomena that a gas when approaching critical pressurebecomes more and more remote from the so-called perfect state, itsaction being characterized by decrease in volume at amuch more rapidrate than the pressure is increased, while at constant temperature, itisknown that under its critical pressure a given weight of gas containsless eat than when under a much lower pressure, say atmosphericpressure. This is due to the internal energy given ofl by the highlycompressed gas in the form of heat, in excess of that energy impartedthereto by the compressor. In the present case, therefore, the

simply by operating the oompreswater-cooling of the fluid from the hi hpressure compresson 26 removes. actual y more heat therefrom than wasgiven to the as during compression, with the result t rat a given weightof fluid entering the coil 25 carries into the system considerably lessheat than the same'weight carries out of the system from the coil 29,notwithstanding t e fact that the temperatures at these points are thesame. As a consequence, the circulating system 25, 26, 28, 29, inaddition to its function as a means for applying the cooling efiect ofthe high pressure gases in passage 3 between the atmosphere and thelevel -Z c to the low pressure. fluid between levels a and 5-0, as willbe hereinafter more specifically set forth, also acts asa;;refrigerating agency to cool the incoming low pressure gas betweenthe atmosphere and the level bc, and to that extent constitutes theequivalent of the external refrigerating agency 13, 14, 15, 16 which isillustrated in Fig. 1. During the starting period the acthe moto'r 184114118m lll e ih l lfpf d t t reat ti ons araa taleathere te at t eetact that; lithe: 7 heat content of t ressuregasiis less. 11:,When theendum havebeen: established, .-a

set"forth, maytrecoverlanamo from theil ighfressureexh pg I I I 5 p ratthe: ,wmpr'es sor', w'o'r cient,=".iit idesire 26,: in such-a mannersure-delivered by IQ0 I- presso1g22 ical pressure; on -above, thusoperation i got-L the; syste by =the;esc.a in lihi'gh isl tre a sageeii,an isinceth si fluid 1X1) co co'oled,,to,thezfiflmp rature;prevailing atevel j-withoutil t nt: eat; ,1 and hereforei I a continuous andsubstantially reversible? manner, since there is, noj oint v where theheat :muSt be mad mflw re ial b ta e at awstationary: temperatuie toone} which is :rising in temperature, ;As shown in the, I a b twen.etmespheris 't mp' r t e tha flu t thefu ai i r systemfiowscountercurrent; however, since 1 the working; fluid; m ne 'Ipas'sa'gesf1 and a andqthat at also; flows Y counter current these rem:

peratures, it lSBVldg I t that, f the to warm t i r L Q ,ference iscompensated "for by the counter u r nt; ow s a-th I t ns er; point d" oui --m y- U ted; S 't L te s Patent No- ,1 ,2, ;8 5; hi dif e e e i eatcapacity between the countercurrentflu ds i P s e en fii s rre ntbe n vthe increased 8 ifio heat of the vapor in system- 95 55} agency d" vaporp g "-B l e "pr sen in j ,bined: exter :opposite directionbetweenithefluids in the coils .25 and 29,. 1

ases

sage

t rn-1 5;- 6, 2-8 ,1 r ma 0 1 this Oolingefiec n me y, to. the l wepl st In oming g u'idin a e w ea l el ai ndb-re The the'va or ,heat transfersystem having been expan edfifroih the critical pressure to the i re dieF ag sabove described e it o e ea:- or in pas t T i and if'thisexpansion is adiabatic with the f external work in the exabout half ofthe fluid will be r the ex ansion, at a temperature 7 pondingtote'temperature at level a.

mixed with the 'vapor'passing from thfe{coil; 21fto"the compressor 22,the whole may reach a'composition just corresponding to, vthe saturatedstate after an adiabatic 7 coin ression'by the Compressor 22. In othersf, superheati'ng of the transfer fluid in system 21, 22, 23, 24 isprevented by x'ture; that portion of the mixture @coil23 effects theevaporationof iqiiid at level- 72 c and is itseltcondensed;

production 0 ander 28 I ris' When thi tad iil ssm'e it will become wetduring expansion,

itsffurther" cooling, by expansion in the nozzle 2e, not only causes it,in the coil 21, to

1 w p t asi reretail n p enaw F je means of the expander 28, and havingbeen as a cooled in coil 25 "below" the critical temperhe temperature a.

logy. with the apparatus shown in threference to the twoindependtorysystems therein shown, it will t that if the cooling effect of ressor 6,Fig." 1 coul cooling eife to the app therefore,

p r i Aswill-be apparent, the remainder of the 115 from compressor 22,consisting of d compressed vapor at a temperature corresponding to thelevel b--c, in

discharg saturate ing low p to demonstrat ,actions above as was the '11condense alike weight of fluid in passagel,

butfalso enables it to effect the cooling of said fluid in passage 1from the temperature 1 2 By" ana Figg'l, 'wi entcircula eji ppe 'ethefiuid from coil 10 after expansion throughexpander 1-1 were applied,as by heat interchange but without admixture, to the transfer fluid onthe suction side of com- 9 then thetwo coils 5 and 12 of d be combined,thus a plying this ct to the cooling of ti: sure working fluid betweenthe levels a and 0;; The action taking place in the apparatus shown in.Fig. 3 closely approximates the action which would take place under theconditions assumed above, which, clearly, correspond exactl to theactual working conditions hereto ore described with reference aratus ofFig. 1. It will be seen, that the admixture of these two circulatingtransfer fluids in efiect imparts on of the refrigerative action of the25, 26, 28, .29 to the system 21, 22, 23',24,this being evident sincethe cooling I efiect'of the first mentioned system is greatheatftransfersysteinherein described,"itjis 1y "increased owing to the wide pressured th gf gid redgbetwen th l vel range through which it operates, and;hea m p elvel; l jid fi c above {set {forth balances any "difference p elow presdescribed actually take place,

7 case in the system illustrated in 1, yet it is clear that the twosystems, bove described,'are based on precisely the same principles, andit is equally true tions of the system quired to operate the transfer isfurnished, in part at least,

' under the handicap of that, by properly proportioning the weights,pressures and temperatures of the circulating and working fluids, allthe actions herein described as taking place can be made substantiallyreversible, as was the case with the system shown in Fig. 1. It will beobvious that by increasing to the necessary extent the weight oftransfer fluid circulated by the combined heat transfer andrefrigerating system 25, 26, 28, 29, the necessary cooling to make upfor the mechanical imperfecmay be supplied, it being assumed, as in theformer case, that the apparatus is effectually insulated from theinleakage of external heat. The power recompressor 22 by the expand or28, working at the same lower temperature as said compressor and betweena much greater range of pressures. The motor 18, utilizing the highpressure gases which have been increased in their available power byheating in the heater 17, may furnish the power for the compressor 26,it being clear that whatever external work is required can be suppliedby the heat added at 17. As in the previous case, the nozzle 24, intheory at least, will furnish the power to drive the pump 4:-

With reference to the applicability of the system, as above described,to the efiicient production of power, and irrespective of its utilityfor refrigeration, liquefaction and separation purposes, it will be seenthat since the gaseous motive fluid is enabled to issue from the primemover 18 in the same condition as that at which it entered theinterchanger, viz, at atmospheric temperature and pressure, thetremendous losses of efiiciency, which characterize other vaporexpansion power cycles, are avoided; in comparison, for instance, withthe usual steam cycle, the present process is far more efli-,

cient, since the former necessarily labors being unable to restore themotive fluid to its original condition with a corresponding extractionof power, i. e., the latent heat of evaporation is largely,irrecoverable. In the present sys tem, however, the latent heatssubstantially balance; most of the heat added at 17 is converted intowork.

While the steps of the to the liquefaction of t have been so fardescribed as applying to the taking in of the working fluid at lowpressure, and its delivery at high pressure, it is obvious that thesystem as a whole possesses the characteristic of reversibility. In thisconnection, referring again to Fig. 1, if it be assumed that fluid underhigh pressure enters passage 3, and discharges from 1 at at 'mosphericpressure; that the external cooling agency 13, i l, 15 and 16 beomitted; and that each expansion device 8 and 11 a working uid,

' perature, but under such hi h rocess, asap lied workajas a compressorand each compressor 4, 6 and 9 becomes an expander; then clearl there isan increase in the amount of wor delivered by 9, working at relativelyhigh temperature, over the corresponding element present in liquefactionsystems of the prior art, and there is a net cooling effect producedbetween the temperature at c and that of the atmosphere. It will beseen, therefore, that certain of the actions and steps characteristic ofthe process may with advantage be applied to the liquefaction and 7separation systems of the prior art, and it is to be understood that myinvention clearly contemplates the foregoing, and is not in any senselimited to a system wherein the outgoing fluid is at higher pressurethan the incoming fluid.

In Fig. 4 I have illustrated diagrammatically the ap lication of certainof the novel steps herein efore mentioned to a liquefaction cycle of theusual type, wherein the working fluid undergoes high initial compressionby a compressor 32, and by means of a water cooler 33 is caused to enterthe interchanger passage 34 at atmospheric tempressure. In the mannercommon to sue prior systems, a portion of this high pressure vapor isexpanded through an expander ,:35 and, after such expansion, is returnedizr 'countercurrent through interchanger passage 36, issuing from thewarm end thereof at atmospheric temperature and pressure. The coolingeffect of this expanded va or portion is thus applied to assist in theiquefaction of the high pressure fluid in passage 34., as indicated insaid figure. In the manner common to such prior systems, expansion ofthe high pressure liquid through .a nozzle 37, or eifiiivalent device,enables the low pressure 'quid thus formed in passage 36, whenevaporated, to afford the necessary cooling effect by heat interchange,to render the process continuous. The a paratus thus far described,while Wholly 'agrammatic in character, and therefore obviouslysusceptible to wide variation, is typical of prior art liquefactioncycles in so far as it may be said to illustrate the basic principiesand actions underlying their operation; and it will be apparent that dueto the much greater specific heat of the incoming high pressure fluid,between, atmospheric temperature and the temperature at e wherecondensation occurs, a. given weight .of countercurrent low pressurevapor 1n passage 36 is called upon to take out from the same weight ofhigh pressure incoming fluid more heat per degree of temperature than itcan absorb. Notwithstandmg this deficiency of cooling efiect between theabove temperatures, there is an excess cooling efiect between the levelsd and 8; therefore, in accordance with my invention the compressor 26may a circulatory system, or other equivalent heat transferring agency,in the presentinstance shown as consisting of coils 38 and 39,compressor 40 and expander 41-, connected as shown, may with advantagebe employed to supplement the cooling eflect upon the incoming e and theatmosphere. may handle an amount 7 as the at the same pressure Thecirculating fluid, after and may work compressor 32. expansion and drawnby the suction of compressor 40 through coil 38, and may be sub-cooledtherein, to such a point thatits subsequent compression will be withoutsuperheating, i. e., the exhaust from the compressor W1]. (1. In passingunder high the coil 39, it cools the incoming high pressure vapor inpassage 34 and is itself warmed thereby to atmospheric temperature; andthereafter is expanded for the purpose of repeating the cycle. In thisway the cooling and liquefaction of the high pressure incoming fluid ispromoted; works at atmospheric returns a much greater amount of workthan the low temperature expander 35, or the expander 11- of Fig. 1.

The refrigerative eflect oft-he system may be utilized in various ways,in the manner common to systems of this class. For example, the lowpressure liquefied working fluid may bewithdrawn through a valve 42, orthe high ressure liquid may be withdrawn through a valve 43, as shownclearly in Figs. 1 and 3. V

An essentially valuable feature of the invention herein described inconnection with Figs. 1 and 3, as compared to processes heretoforeknown, resides in the fact that the working fluid may be condensed andseparated, if desired, under hi h pressure; more-- over if the outgoingfiui from a liquefaction or separation system using my process wereexpanded through an expander, such as the expander 19 of Fig. 2, thesystem would require for its operation the expenditure of only a verysmall pro )ortion of the power required to operate or inary systems ofthe same capacity. Obviously, the power thus required would be entirelyindependent of any power recovered, as above described, by the use ofexternal heat.

As applied to the simple compression of a gas, for any purposewhatsoever, the present invention permits the use of substantiallyadiabatic compressors and expanders working below atmospherictemperature. In the form of apparatus shown in Fig. 3,

be made very small, since it operates with a fluid already under highcompression, and thus it may be much be at temperature pressure throughfluid between the temperature The compressor 40 of fluid equivalent tothe working fluid handled by compressor 32 cooling .in expander 41, is 1above described and the expander 41, since .it'

temperature, actually more nearly isothermal in its action than the highpressure compressors used in the ordinary processes for the directpreliminary compression of the fluids therein used. The exhaust frommotor 18 may, if desired, be returned through the interchanger for useover and over in the systermas indicated in Fig. 3..

1. In apparatus of the class described, the

combination with means for circulating a gaseous working fluid incountercurrent, to rocure interchange of heat between heat absorbing andheat rejecting portions thereof, of means for applying the coolingefl'ect of the heat absorbing portion at a high temperature to effectthe cooling of the heat reecting portion at a lower temperature.

2. In apparatus of the class described, means for circulating a gaseousworking fluid in countercurrent, means for circulating a fluid in heatexchanging relation to a portion of the incoming working fluid betweengiven tem eratures, and means for cooling said circu ating fluid by heatinterchange with a portion of the outgoing working fluid between othertemperatures.

3. In apparatus of the class described, means for circulating a gaseousworking fluid in countercurrent, means for circulating a fluid in heatexchanging relation to a portion of the incoming fluid at a lowtemperature, and means for cooling said circulating fluid by heatinterchange with a portion of the outgoing working fluid at a highertemperature.

4. In apparatus of the class described, means for circulating a gaseousworking fluid in countercurrent, to procure heat inter-- change betweenheat absorbing and heat rejecting portions thereof, and means fortransferring heat contents from said heat rcjecting portion underatmospheric pressure to said heat absorbing portion under a higherpressure, whereby to liquefy said heat re]ect1ng portlon.

5.. In apparatus of the class described, the combination with means forcirculating a gaseous working fluid in countercurrent, of means forcirculating fluid in heat exchangin relation to a portion of saidworking fluid, to extract the latent'heat of condensation therefrom,means forv increasing the pressure on said circulating fluid after suchextraction, means for removing the superheat from said circulatingfluid, and means for transferring said extracted heat to the liquefiedworking fluid.

6. In apparatus of the class described, the

7 means for raising the pressure'lojn said culatin fluid after suchextraction, means for transferring the e rtracted heatto circulatingfluid to preventitssuperheating,

7. In apparatus of the class described, means for liquefyinga I gaseousvwoi'king fluid under atmospheric pressure, means for raising thepressure oni'the liquid" thus formed, means for evaporatin said liquidunder its increased pressure, and means for transferring the heat fromthe gaseous orking fluid undergoing liquefaction at a low temperature,to said high pressure evaporate at a higher temperature.

8. In apparatus of the class described, means for liquefying a gaseousworking fluid, means for circulating the evaporate from the liquefiedfluid in countercurrent to the gaseous working fluid undergoingliquefaction, and means for transferring heat from the latter betweengiven temperatures, to said evaporate between other temperatures.

9. In apparatus of the class described, means for liquefying a gaseousworking fluid, means for increasing the pressure on the liquid thusformed, means for trans ferring the latent heat of condensation of thefluid being liquefied to the liquid under such increased pressure toeffect evaporation of the latter, and means for applying the coolingeflect of said evaporate at a high temperature to the gaseous workingfluid at a lower temperature. 4

10. In apparatus of the class described, means for liquefying a gaseousworking fluid, means for increasing the pressure on the liquid thusformed, means for evaporating said liquid under its increased pressure,and means for transferring to said evaporate, at a high temperature, theheat extracted from the gaseous working fluid at a lower temperature.

11. In apparatus of the class described, means for liquefying a gaseousworking fluid, means for increasing the pressure on the liquid thusformed, means for evaporating said liquid under its increased pressure,means for transferring to said evaporate, at a high temperature, theheat extracted from the gaseous working fluid at a lower temperature andmeans for ex )andin said evaporate for the production of power.

12. In ap aratus of the class described, means for iquefying a gaseousWorking fluid under lowpressure. means for increasing the pressure onthe liquid thus formed, means for evaporating said liquid under itsincreased pressure, means for cooling the low pressure working fluid tothe temperature of low pressure liquefaction by transfer of its heat tosaid high pressure evaporate at a higher temperature, means forexternally heating said high pressure evaporate, and

the combination with means "f means forexpanding said heated evaporateforftl'ie'production' of'usefuli'work.

l3": Infapparatus of 'the' class'adescribed,

. nf the' means for 1rdulaitingat fluid is; heat ex changing relation.to said liquid to evaporate I means; for ii-pplyingth'ecoo'ling' effectof said evaporate to said circulatingthe same;

fluid, and means for cooling and condensing the gaseous working fluid byheat inter" change with said circulating fluid.

14. In apparatus of the means for liquefying a gaseous working fluid,means for raising the pressure on the liquefying a class described,

liquid thus formed, means for circulating a fluid in heat exchangingrelation to different portions of said Working fluid, means fortransferring latent heat from the gaseous working fluid to saidcirculating fluid, means for compressing said circulating fluid, meansfor transferring the heat absorbed by said circulating fluid to theliquid working fluid under its increased pressure, to effect theevaporation thereof, means for circulating another fluid inheat-exchanging relation to said evaporate, and means for cooling saidfirst circulating fluid before compression thereof by heat interchangewith said second circulating fluid.

15. In apparatus of the class described, means for liquefying a gaseousworking fluid, means for circulating a portion of said fluid underatmospheric pressure in countercurrent to another portion under a hi herpressure, means for circulating fluids in cat exchanging relation tosaid first portion of the working fluid, to cool and liquefy the same,absorbed by said circulating fluids to said high pressure portion of theworking fluid.

16. In apparatus of the class described, means for circulating a ingfluid in countercurrent to effect heat interchange between incoming andoutgoin portions thereof, means for discharging said outgoing portion ata higher pressure than said incoming portion, means for eiitracting heatfrom one portion between given temperatures, and means for transferringsaid extracted heat to said other portion between differenttemperatures.

17. In apparatus of the class described, means for liquefying a gaseousworking fluid underatmospheric pressure, means for evaporating saidliquefied working fluid, and means for transferring heat from thegaseous working fluid at a low temperature to said evaporate at a highertemperature.

18. In apparatus of the class described, means for passing a gaseousworking fluid through the liquid state, means for alternatelycompressing and expanding a portion thereof, and means for circulatingsaid porand means for transferring the heat 7 gaseous worktion in heatexchanging re positions of the working after liquefaction.

19. In apparatus of the class described,

lation to gaseo fluid before an us and after lique'f culating fluid.

5 means for passin a gaseous working fluid through the liqui state, inga fluid gaseous portions of the 'worki Witnesses to E. A. W.

(i nately compressing and Dated this 25th day action, and means foralterexpanding said cirof January, 1919. FRED E. NORTON.

J EFFERIES,

JOSEPH A. RAY.

